20009172 has 24 divisors (see below), whose sum is σ = 48718656. Its totient is φ = 6379648.

The previous prime is 20009137. The next prime is 20009173. The reversal of 20009172 is 27190002.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20009173) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35973 + ... + 36524.

It is an arithmetic number, because the mean of its divisors is an integer number (2029944).

Almost surely, 2^20009172 is an apocalyptic number.

It is an amenable number.

20009172 is an abundant number, since it is smaller than the sum of its proper divisors (28709484).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20009172 is a wasteful number, since it uses less digits than its factorization.

20009172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72527 (or 72525 counting only the distinct ones).

The product of its (nonzero) digits is 252, while the sum is 21.

The square root of 20009172 is about 4473.1612982319. The cubic root of 20009172 is about 271.4832497153.

Adding to 20009172 its reverse (27190002), we get a palindrome (47199174).

The spelling of 20009172 in words is "twenty million, nine thousand, one hundred seventy-two".